From nobody Wed Feb 11 01:25:57 2026 Received: from mail-oo1-f71.google.com (mail-oo1-f71.google.com [209.85.161.71]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B4B092D1913 for ; Tue, 10 Feb 2026 02:15:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.71 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770689705; cv=none; b=pyYVk1Bpf+Whq+5tP0zGfuAIRpc4QPfwfhJ2r4SeU18wpTz+nninPGd9i3YXezcI7Lwvrs3z8uai/vIffT4Hk+wbXZThjNjDs8ukoACRHrrrQSDoX3Y+6y+a8YqFMuCyZM+5f0sexXO3cSPFbp9Lx+DQjdCCCW18Pzm1yUBIlsU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770689705; c=relaxed/simple; bh=eKtQi4JyzNIJh7ulHtSQBhU5GqlXZN4gns3J3F2bTw8=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=NtrXx6p8xutg5gDbwjUjSgL8XXoh0At+k5XY23Gn2BV6mx0qn+QCBAo/r+b1sipWbv2ojKC4RGVUC1Vxy/ZWmF+SWzEyoEvFXv67caIYX8HlqlNGckhllzSeVzjtTRSiV7W1k8CjUga9T6eaMWGLE1k0U0/aPNE8/IUjNYFvjqc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.161.71 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oo1-f71.google.com with SMTP id 006d021491bc7-66cc1133633so8825713eaf.1 for ; Mon, 09 Feb 2026 18:15:03 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1770689702; x=1771294502; h=to:from:subject:message-id:in-reply-to:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=YhXXznGJ1rFCG2cHpV39UEa19JGlF+Ku/ien/sp/DZ8=; b=Lfod6De5i175pB1uc0qKX8XesKq6bbRvft0kED0hUsrK1LFUO/8m/N6TOCI8eMnmob nI6FX95ztBQ/MtWqi1CbLjCKjYNnSdNq5mluc52O/CKpeLVVKrq41LlVYSNTUk6ifMVc Ydws8AZoowrOXGFYSOY3mFtIzs05NZ0EPxjLkrTVXrwxBNNK6PTvSg1EpCiBVpGc8POa pDABKmh19mYLoZn7Katbg2aJRsXigr6CsZng/ZTDG1I0buz58uW0MYi6N3RC6sb0MvLx WjlBhRKYG/YKZvkdQdqlJL4GCaKynlFuS/eRCFC8v/r7HkiPZozhCCH6V79KuuuvJ/vF Gx5Q== X-Gm-Message-State: AOJu0YyJev2E2170MotOaWJ7Z0gvoMs8ZZZhLLqObYklnxT2rImcQCCH B22tg///blAhsXz06VEFlNdZULq2Y85j/ZgW3YdKHztrk/zWDohdZJk+QMgGBcZ7XlQMvh0qbiy QvcF5eAK8paKIHq//6Ii4SgJ6BSba6kxd77zhNjGYacvHp8WQKCbnGgIvsKU= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:1614:b0:668:d715:108f with SMTP id 006d021491bc7-66d0d20481bmr5421546eaf.73.1770689702616; Mon, 09 Feb 2026 18:15:02 -0800 (PST) Date: Mon, 09 Feb 2026 18:15:02 -0800 In-Reply-To: <698a0023.050a0220.3b3015.0078.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <698a94a6.050a0220.3b3015.0085.GAE@google.com> Subject: Forwarded: Re: [syzbot] [rds?] general protection fault in rds_tcp_accept_one From: syzbot To: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" For archival purposes, forwarding an incoming command email to linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com. *** Subject: Re: [syzbot] [rds?] general protection fault in rds_tcp_accept_one Author: allison.henderson@oracle.com #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.gi= t main commit 86b003db7ed7f474c3f462643c2912ffdeb2f876 Author: Allison Henderson Date: Mon Feb 9 18:20:42 2026 -0700 net/rds: Fix NULL pointer dereference in rds_tcp_accept_one =20 Hold a local reference to new_sock->sk before installing callbacks in rds_tcp_accept_one. After rds_tcp_set_callbacks() or rds_tcp_reset_callbacks(), tc->t_sock is set to new_sock which may race with the shutdown path. A concurrent rds_tcp_conn_path_shutdown() may call sock_release(), which sets new_sock->sk =3D NULL and frees sk. =20 Subsequent accesses to new_sock->sk->sk_state dereference NULL, causing the null dereference. So a local sock reference with sock_hold() before installing callbacks will prevent the race. =20 Fixes: 826c1004d4ae ("net/rds: rds_tcp_conn_path_shutdown must not disc= ard messages") Reported-by: syzbot+96046021045ffe6d7709@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=3D96046021045ffe6d7709 Signed-off-by: Allison Henderson diff --git a/net/rds/tcp_listen.c b/net/rds/tcp_listen.c index 6fb5c928b8fd..cdc86473a1ba 100644 --- a/net/rds/tcp_listen.c +++ b/net/rds/tcp_listen.c @@ -177,6 +177,7 @@ int rds_tcp_accept_one(struct rds_tcp_net *rtn) struct rds_tcp_connection *rs_tcp =3D NULL; int conn_state; struct rds_conn_path *cp; + struct sock *sk; struct in6_addr *my_addr, *peer_addr; #if !IS_ENABLED(CONFIG_IPV6) struct in6_addr saddr, daddr; @@ -298,6 +299,14 @@ int rds_tcp_accept_one(struct rds_tcp_net *rtn) rds_conn_path_drop(cp, 0); goto rst_nsk; } + /* Hold a local reference to sk before setting callbacks. Once callbacks + * are set, it is possible for a concurrent rds_tcp_conn_path_shutdown + * call to release the new_sock->sk and set it to NULL. So we use + * a local sk here to avoid racing with callbacks + */ + sk =3D new_sock->sk; + sock_hold(sk); + if (rs_tcp->t_sock) { /* Duelling SYN has been handled in rds_tcp_accept_one() */ rds_tcp_reset_callbacks(new_sock, cp); @@ -316,13 +325,15 @@ int rds_tcp_accept_one(struct rds_tcp_net *rtn) * knowing that "rds_tcp_conn_path_shutdown" will * dequeue pending messages. */ - if (new_sock->sk->sk_state =3D=3D TCP_CLOSE_WAIT || - new_sock->sk->sk_state =3D=3D TCP_LAST_ACK || - new_sock->sk->sk_state =3D=3D TCP_CLOSE) + if (READ_ONCE(sk->sk_state) =3D=3D TCP_CLOSE_WAIT || + READ_ONCE(sk->sk_state) =3D=3D TCP_LAST_ACK || + READ_ONCE(sk->sk_state) =3D=3D TCP_CLOSE) rds_conn_path_drop(cp, 0); else queue_delayed_work(cp->cp_wq, &cp->cp_recv_w, 0); =20 + sock_put(sk); + new_sock =3D NULL; ret =3D 0; if (conn->c_npaths =3D=3D 0)